The present invention relates to the field of gun barrels for the launching of projectiles.
It has long been thought possible to use large guns to assist with the launching of devices into orbit. One means of potentially accomplishing this is to use a very large gun barrel to launch a projectile, such as a rocket with a satellite payload, beyond the lower atmosphere of the earth, and then to fire the rocket so that it will cause the satellite to reach orbital velocity and subsequently enter into an orbital path. The rocket is launched to a height that is above the lower atmosphere, as it is in the lower atmosphere that most drag occurs and where most rockets use up a large quantity of their fuel. By firing the rocket in the near vacuum of the upper atmosphere, less fuel is required by the rocket to achieve orbital velocity. Since a gun barrel can be used more than once, gun launching provides an economical first stage for launching satellites. Additionally, a gun launch can be used in almost any weather condition.
Long-range artillery capable of launching projectiles a significant distance was first developed and used in WW I. For example, the Paris gun, when fired at an angle of 50 degrees, was able to send a projectile to an altitude of 43.2 km, well past the 12 km that is generally considered to be the “lower atmosphere”. The Max E gun could fire a 740 kg projectile to a maximum range of 47 km. The Paris Gun and the Max E, if fired at a 90-degree angle to the earth's surface could have fired projectiles past the lower atmosphere. The 800 mm Gustav developed in WW II could fire a 4800 kg shell a distance of 47 km, and a 7100 kg shell a distance of 38 km.
In the early 1960's, Gerald Bull was involved with a project called HARP, an acronym for High Altitude Research Project, which program involved the use of large guns to fire projectiles and rockets to high altitudes. The HARP program was cancelled before its goal of achieving orbital entry of a device was obtained, because the system was too expensive and the available technology would not support further research. However, altitudes of 110 miles were reached, with 400-pound projectiles.
Advances in the development of rockets, new types of rocket fuels, new propellants for artillery, and advances in the design of smaller satellites, such as nano and pico satellites, which can weigh as little at 10 ounces, now make the gun-assisted launching of orbital devices, such as satellites, possible.
One component of a gun launch apparatus for the launching of a projectile is the gun barrel. To be able to assist in achieving orbital launching of a device, the gun barrel must be very large. Traditionally, very large gun barrels have been comprised of steel, to provide the required strength and rigidity. However, steel gun barrels of the size required for gun-assisted orbital launching are expensive to make and heavy. The weight of a large steel gun barrel is a factor that significantly interferes with the ability to move or vary the location of the gun barrel, and the latter problem limits the potential to use the same gun barrel to repeatedly launch satellites into orbit, as the barrel is always pointed to the same position.
The cost of putting a satellite into orbit is currently very high. Advances in rocket and satellite technology suggest that it is worthwhile to revisit the concept of using large guns to assist with the launching of satellites into orbit, particularly if it will lower the cost of satellite launching. One way to lower the cost is to make a gun barrel that is less expensive than a steel gun barrel.